objtool: Add CONFIG_OBJTOOL

Now that stack validation is an optional feature of objtool, add
CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with
it.

CONFIG_STACK_VALIDATION can now be considered to be frame-pointer
specific.  CONFIG_UNWINDER_ORC is already inherently valid for live
patching, so no need to "validate" it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com

diff --git a/Makefile b/Makefile
index fa5112a..2507076 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1302,7 +1302,7 @@ install: sub_make_done :=
 # ---------------------------------------------------------------------------
 # Tools
 
-ifdef CONFIG_STACK_VALIDATION
+ifdef CONFIG_OBJTOOL
 prepare: tools/objtool
 endif
 

diff --git a/arch/Kconfig b/arch/Kconfig
index 29b0167..04cdef1 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1028,11 +1028,14 @@ config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
        depends on MMU
        select ARCH_HAS_ELF_RANDOMIZE
 
+config HAVE_OBJTOOL
+       bool
+
 config HAVE_STACK_VALIDATION
        bool
        help
-         Architecture supports the 'objtool check' host tool command, which
-         performs compile-time stack metadata validation.
+         Architecture supports objtool compile-time frame pointer rule
+         validation.
 
 config HAVE_RELIABLE_STACKTRACE
        bool
@@ -1302,6 +1305,7 @@ config HAVE_STATIC_CALL
 config HAVE_STATIC_CALL_INLINE
        bool
        depends on HAVE_STATIC_CALL
+       select OBJTOOL
 
 config HAVE_PREEMPT_DYNAMIC
        bool

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4bed3ab..43e26ee 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -188,7 +188,7 @@ config X86
        select HAVE_CONTEXT_TRACKING            if X86_64
        select HAVE_CONTEXT_TRACKING_OFFSTACK   if HAVE_CONTEXT_TRACKING
        select HAVE_C_RECORDMCOUNT
-       select HAVE_OBJTOOL_MCOUNT              if STACK_VALIDATION
+       select HAVE_OBJTOOL_MCOUNT              if HAVE_OBJTOOL
        select HAVE_BUILDTIME_MCOUNT_SORT
        select HAVE_DEBUG_KMEMLEAK
        select HAVE_DMA_CONTIGUOUS
@@ -231,6 +231,7 @@ config X86
        select HAVE_MOVE_PMD
        select HAVE_MOVE_PUD
        select HAVE_NMI
+       select HAVE_OBJTOOL                     if X86_64
        select HAVE_OPTPROBES
        select HAVE_PCSPKR_PLATFORM
        select HAVE_PERF_EVENTS
@@ -239,17 +240,17 @@ config X86
        select HAVE_PCI
        select HAVE_PERF_REGS
        select HAVE_PERF_USER_STACK_DUMP
-       select MMU_GATHER_RCU_TABLE_FREE                if PARAVIRT
+       select MMU_GATHER_RCU_TABLE_FREE        if PARAVIRT
        select HAVE_POSIX_CPU_TIMERS_TASK_WORK
        select HAVE_REGS_AND_STACK_ACCESS_API
-       select HAVE_RELIABLE_STACKTRACE         if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
+       select HAVE_RELIABLE_STACKTRACE         if UNWINDER_ORC || STACK_VALIDATION
        select HAVE_FUNCTION_ARG_ACCESS_API
        select HAVE_SETUP_PER_CPU_AREA
        select HAVE_SOFTIRQ_ON_OWN_STACK
        select HAVE_STACKPROTECTOR              if CC_HAS_SANE_STACKPROTECTOR
-       select HAVE_STACK_VALIDATION            if X86_64
+       select HAVE_STACK_VALIDATION            if HAVE_OBJTOOL
        select HAVE_STATIC_CALL
-       select HAVE_STATIC_CALL_INLINE          if HAVE_STACK_VALIDATION
+       select HAVE_STATIC_CALL_INLINE          if HAVE_OBJTOOL
        select HAVE_PREEMPT_DYNAMIC_CALL
        select HAVE_RSEQ
        select HAVE_SYSCALL_TRACEPOINTS
@@ -268,7 +269,6 @@ config X86
        select RTC_MC146818_LIB
        select SPARSE_IRQ
        select SRCU
-       select STACK_VALIDATION                 if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
        select SYSCTL_EXCEPTION_TRACE
        select THREAD_INFO_IN_TASK
        select TRACE_IRQFLAGS_SUPPORT
@@ -459,6 +459,7 @@ config GOLDFISH
 
 config RETPOLINE
        bool "Avoid speculative indirect branches in kernel"
+       select OBJTOOL if HAVE_OBJTOOL
        default y
        help
          Compile kernel with the retpoline compiler options to guard against
@@ -472,6 +473,7 @@ config CC_HAS_SLS
 config SLS
        bool "Mitigate Straight-Line-Speculation"
        depends on CC_HAS_SLS && X86_64
+       select OBJTOOL if HAVE_OBJTOOL
        default n
        help
          Compile the kernel with straight-line-speculation options to guard
@@ -1819,6 +1821,7 @@ config ARCH_RANDOM
 config X86_SMAP
        def_bool y
        prompt "Supervisor Mode Access Prevention" if EXPERT
+       select OBJTOOL if HAVE_OBJTOOL
        help
          Supervisor Mode Access Prevention (SMAP) is a security
          feature in newer Intel processors.  There is a small
@@ -1855,9 +1858,10 @@ config CC_HAS_IBT
 config X86_KERNEL_IBT
        prompt "Indirect Branch Tracking"
        bool
-       depends on X86_64 && CC_HAS_IBT && STACK_VALIDATION
+       depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
        # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
        depends on !LD_IS_LLD || LLD_VERSION >= 140000
+       select OBJTOOL
        help
          Build the kernel with support for Indirect Branch Tracking, a
          hardware support course-grain forward-edge Control Flow Integrity

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index d3a6f74..d872a75 100644 (file)
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -237,7 +237,7 @@ choice
 config UNWINDER_ORC
        bool "ORC unwinder"
        depends on X86_64
-       select STACK_VALIDATION
+       select OBJTOOL
        help
          This option enables the ORC (Oops Rewind Capability) unwinder for
          unwinding kernel stack traces.  It uses a custom data format which is

diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 0449b12..3ce0e67 100644 (file)
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -20,7 +20,7 @@
        _ASM_PTR "%c0 + %c1 - .\n\t"                    \
        ".popsection \n\t"
 
-#ifdef CONFIG_STACK_VALIDATION
+#ifdef CONFIG_OBJTOOL
 
 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
@@ -34,7 +34,7 @@ l_yes:
        return true;
 }
 
-#else
+#else /* !CONFIG_OBJTOOL */
 
 static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
 {
@@ -48,7 +48,7 @@ l_yes:
        return true;
 }
 
-#endif /* STACK_VALIDATION */
+#endif /* CONFIG_OBJTOOL */
 
 static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
 {

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index d374cb3..3c66073 100644 (file)
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -338,7 +338,7 @@ next:
        }
 }
 
-#if defined(CONFIG_RETPOLINE) && defined(CONFIG_STACK_VALIDATION)
+#if defined(CONFIG_RETPOLINE) && defined(CONFIG_OBJTOOL)
 
 /*
  * CALL/JMP *%\reg
@@ -507,11 +507,11 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
        }
 }
 
-#else /* !RETPOLINES || !CONFIG_STACK_VALIDATION */
+#else /* !CONFIG_RETPOLINE || !CONFIG_OBJTOOL */
 
 void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { }
 
-#endif /* CONFIG_RETPOLINE && CONFIG_STACK_VALIDATION */
+#endif /* CONFIG_RETPOLINE && CONFIG_OBJTOOL */
 
 #ifdef CONFIG_X86_KERNEL_IBT
 

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 219aa5d..01ce94b 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -109,7 +109,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #endif
 
 /* Unreachable code */
-#ifdef CONFIG_STACK_VALIDATION
+#ifdef CONFIG_OBJTOOL
 /*
  * These macros help objtool understand GCC code flow for unreachable code.
  * The __COUNTER__ based labels are a hack to make each instance of the macros
@@ -128,10 +128,10 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 /* Annotate a C jump table to allow objtool to follow the code flow */
 #define __annotate_jump_table __section(".rodata..c_jump_table")
 
-#else
+#else /* !CONFIG_OBJTOOL */
 #define annotate_unreachable()
 #define __annotate_jump_table
-#endif
+#endif /* CONFIG_OBJTOOL */
 
 #ifndef unreachable
 # define unreachable() do {            \

diff --git a/include/linux/instrumentation.h b/include/linux/instrumentation.h
index 24359b4..9111a37 100644 (file)
--- a/include/linux/instrumentation.h
+++ b/include/linux/instrumentation.h
@@ -2,7 +2,7 @@
 #ifndef __LINUX_INSTRUMENTATION_H
 #define __LINUX_INSTRUMENTATION_H
 
-#if defined(CONFIG_DEBUG_ENTRY) && defined(CONFIG_STACK_VALIDATION)
+#ifdef CONFIG_VMLINUX_VALIDATION
 
 #include <linux/stringify.h>
 
@@ -53,9 +53,9 @@
                     ".popsection\n\t" : : "i" (c));                    \
 })
 #define instrumentation_end() __instrumentation_end(__COUNTER__)
-#else
+#else /* !CONFIG_VMLINUX_VALIDATION */
 # define instrumentation_begin()       do { } while(0)
 # define instrumentation_end()         do { } while(0)
-#endif
+#endif /* CONFIG_VMLINUX_VALIDATION */
 
 #endif /* __LINUX_INSTRUMENTATION_H */

diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 586d357..977d90b 100644 (file)
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -38,7 +38,7 @@ struct unwind_hint {
 #define UNWIND_HINT_TYPE_REGS_PARTIAL  2
 #define UNWIND_HINT_TYPE_FUNC          3
 
-#ifdef CONFIG_STACK_VALIDATION
+#ifdef CONFIG_OBJTOOL
 
 #ifndef __ASSEMBLY__
 
@@ -157,7 +157,7 @@ struct unwind_hint {
 
 #endif /* __ASSEMBLY__ */
 
-#else /* !CONFIG_STACK_VALIDATION */
+#else /* !CONFIG_OBJTOOL */
 
 #ifndef __ASSEMBLY__
 
@@ -179,6 +179,6 @@ struct unwind_hint {
 .endm
 #endif
 
-#endif /* CONFIG_STACK_VALIDATION */
+#endif /* CONFIG_OBJTOOL */
 
 #endif /* _LINUX_OBJTOOL_H */

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 2c43e32..2956bc2 100644 (file)
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -728,6 +728,7 @@ config FTRACE_MCOUNT_USE_OBJTOOL
        depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
        depends on !FTRACE_MCOUNT_USE_CC
        depends on FTRACE_MCOUNT_RECORD
+       select OBJTOOL
 
 config FTRACE_MCOUNT_USE_RECORDMCOUNT
        def_bool y

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 075cd25..c0e4e47 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -485,24 +485,25 @@ config FRAME_POINTER
          larger and slower, but it gives very useful debugging information
          in case of kernel bugs. (precise oopses/stacktraces/warnings)
 
+config OBJTOOL
+       bool
+
 config STACK_VALIDATION
        bool "Compile-time stack metadata validation"
-       depends on HAVE_STACK_VALIDATION
+       depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
+       select OBJTOOL
        default n
        help
-         Add compile-time checks to validate stack metadata, including frame
-         pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure
-         that runtime stack traces are more reliable.
-
-         This is also a prerequisite for generation of ORC unwind data, which
-         is needed for CONFIG_UNWINDER_ORC.
+         Validate frame pointer rules at compile-time.  This helps ensure that
+         runtime stack traces are more reliable.
 
          For more information, see
          tools/objtool/Documentation/stack-validation.txt.
 
 config VMLINUX_VALIDATION
        bool
-       depends on STACK_VALIDATION && DEBUG_ENTRY
+       depends on HAVE_OBJTOOL && DEBUG_ENTRY
+       select OBJTOOL
        default y
 
 config VMLINUX_MAP
@@ -2035,10 +2036,11 @@ config KCOV
        bool "Code coverage for fuzzing"
        depends on ARCH_HAS_KCOV
        depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
-       depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \
+       depends on !ARCH_WANTS_NO_INSTR || HAVE_OBJTOOL || \
                   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
        select DEBUG_FS
        select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
+       select OBJTOOL if HAVE_OBJTOOL
        help
          KCOV exposes kernel code coverage information in a form suitable
          for coverage-guided fuzzing (randomized testing).

diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index de02244..901c3b5 100644 (file)
--- a/lib/Kconfig.kcsan
+++ b/lib/Kconfig.kcsan
@@ -187,7 +187,8 @@ config KCSAN_WEAK_MEMORY
        # We can either let objtool nop __tsan_func_{entry,exit}() and builtin
        # atomics instrumentation in .noinstr.text, or use a compiler that can
        # implement __no_kcsan to really remove all instrumentation.
-       depends on STACK_VALIDATION || CC_IS_GCC || CLANG_VERSION >= 140000
+       depends on HAVE_OBJTOOL || CC_IS_GCC || CLANG_VERSION >= 140000
+       select OBJTOOL if HAVE_OBJTOOL
        help
          Enable support for modeling a subset of weak memory, which allows
          detecting a subset of data races due to missing memory barriers.

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index f3c57ed..c4fe15d 100644 (file)
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -94,7 +94,7 @@ config UBSAN_UNREACHABLE
        bool "Perform checking for unreachable code"
        # objtool already handles unreachable checking and gets angry about
        # seeing UBSan instrumentation located in unreachable places.
-       depends on !STACK_VALIDATION
+       depends on !(OBJTOOL && (STACK_VALIDATION || UNWINDER_ORC || X86_SMAP))
        depends on $(cc-option,-fsanitize=unreachable)
        help
          This option enables -fsanitize=unreachable which checks for control

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index d5e15ae..0f73e02 100644 (file)
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -222,7 +222,7 @@ cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),
        $(sub_cmd_record_mcount))
 endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 
-ifdef CONFIG_STACK_VALIDATION
+ifdef CONFIG_OBJTOOL
 
 objtool := $(objtree)/tools/objtool/objtool
 
@@ -241,7 +241,7 @@ objtool_args =                                                              \
 cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)
 cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
 
-endif # CONFIG_STACK_VALIDATION
+endif # CONFIG_OBJTOOL
 
 ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)
 

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 0140bfa..5101a7f 100755 (executable)
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -108,8 +108,11 @@ objtool_link()
        local objtoolcmd;
        local objtoolopt;
 
-       if is_enabled CONFIG_STACK_VALIDATION && \
-          ( is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT ); then
+       if ! is_enabled CONFIG_OBJTOOL; then
+               return;
+       fi
+
+       if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
 
                # Don't perform vmlinux validation unless explicitly requested,
                # but run objtool on vmlinux.o now that we have an object file.
@@ -126,10 +129,23 @@ objtool_link()
                        objtoolopt="${objtoolopt} --orc"
                fi
 
+               if is_enabled CONFIG_RETPOLINE; then
+                       objtoolopt="${objtoolopt} --retpoline"
+               fi
+
+               if is_enabled CONFIG_SLS; then
+                       objtoolopt="${objtoolopt} --sls"
+               fi
+
                if is_enabled CONFIG_STACK_VALIDATION; then
                        objtoolopt="${objtoolopt} --stackval"
                fi
 
+               if is_enabled CONFIG_X86_SMAP; then
+                       objtoolopt="${objtoolopt} --uaccess"
+               fi
+
+
                objtoolopt="${objtoolopt} --lto"
        fi
 
@@ -139,18 +155,6 @@ objtool_link()
 
        if [ -n "${objtoolopt}" ]; then
 
-               if is_enabled CONFIG_RETPOLINE; then
-                       objtoolopt="${objtoolopt} --retpoline"
-               fi
-
-               if is_enabled CONFIG_SLS; then
-                       objtoolopt="${objtoolopt} --sls"
-               fi
-
-               if is_enabled CONFIG_X86_SMAP; then
-                       objtoolopt="${objtoolopt} --uaccess"
-               fi
-
                if ! is_enabled CONFIG_FRAME_POINTER; then
                        objtoolopt="${objtoolopt} --no-fp"
                fi

diff --git a/scripts/package/builddeb b/scripts/package/builddeb
index 91a502b..67cd420 100755 (executable)
--- a/scripts/package/builddeb
+++ b/scripts/package/builddeb
@@ -67,7 +67,7 @@ deploy_kernel_headers () {
        ) > debian/hdrsrcfiles
 
        {
-               if is_enabled CONFIG_STACK_VALIDATION; then
+               if is_enabled CONFIG_OBJTOOL; then
                        echo tools/objtool/objtool
                fi
 

diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
index 586d357..977d90b 100644 (file)
--- a/tools/include/linux/objtool.h
+++ b/tools/include/linux/objtool.h
@@ -38,7 +38,7 @@ struct unwind_hint {
 #define UNWIND_HINT_TYPE_REGS_PARTIAL  2
 #define UNWIND_HINT_TYPE_FUNC          3
 
-#ifdef CONFIG_STACK_VALIDATION
+#ifdef CONFIG_OBJTOOL
 
 #ifndef __ASSEMBLY__
 
@@ -157,7 +157,7 @@ struct unwind_hint {
 
 #endif /* __ASSEMBLY__ */
 
-#else /* !CONFIG_STACK_VALIDATION */
+#else /* !CONFIG_OBJTOOL */
 
 #ifndef __ASSEMBLY__
 
@@ -179,6 +179,6 @@ struct unwind_hint {
 .endm
 #endif
 
-#endif /* CONFIG_STACK_VALIDATION */
+#endif /* CONFIG_OBJTOOL */
 
 #endif /* _LINUX_OBJTOOL_H */